Indiana University fingerprint research gives experts the edge

Findings could play a role in Daubert hearings

BLOOMINGTON, Ind. -- Fingerprint examination research by an Indiana University psychology professor could bolster the admissibility of fingerprint evidence during court proceedings.

Fingerprint examination is one of several forensic science techniques often questioned during Daubert hearings. A Daubert hearing is conducted within a hearing so a judge can determine whether the scientific evidence in question is relevant and reliable. Daubert hearings refer to the 1993 civil case Daubert v. Merrell Dow Pharmaceuticals and initially applied only to federal cases. Many state and local jurisdictions have since adopted the standards.

Thomas Busey, an associate professor in the Department of Psychology at IU Bloomington, said some attorneys argue that fingerprint examination does not require special expertise, so fingerprints should be presented to jurors without any interpretation or opinion from experts. His research has found, however, that experts analyze fingerprints significantly more effectively than novices -- even using different brain processes, according to the electrophysiological results of his research.

His findings were published in the February edition of the journal Vision Research. John Vanderkolk, co-author of the Vision Research article and a veteran latent fingerprint examiner, said the reliability of forensic physical comparison sciences, whether involving fingerprints, handwriting, tire tracks or other comparisons, is an international issue that he is eager to see resolved.

"There's an international desire among the forensic science community to have more research conducted on forensic science identifications," said Vanderkolk, who lectures nationally and abroad on the subject. Vanderkolk is the laboratory manager for the Indiana State Police at Fort Wayne.

Fingerprints contain a very regular structure that is unique, even among identical twins. Fingerprint examiners spend a great deal of time exposing their visual systems to this regular structure. The brain may adjust its processing in response to this regular visual diet, Busey said, adapting its behavior through a process called perceptual learning.

In their studies, Busey and Vanderkolk designed two experiments that distilled the essential elements of a real fingerprint identification. This research found that the experts used a brain process called configural processing, which involves relating parts of the fingerprint to each other. Fingerprints, like faces, have standard features, Busey said, and it has long been known that most people process faces configurally. Artists take advantage of this fact when they turn an object upside down in order to see it in a different way.

In their brain-recording experiment, the authors looked for an electrophysiological signature in a particular part of the brain called the occipital/parietal region. This signature is apparent for faces in all normal subjects, but appears only for fingerprints in fingerprint examiners. Thus it appears, said Busey, that fingerprint experts see fingerprints in a qualitatively different way than novices.

The configural processing used by experts lets them consider the bigger picture when focusing on specific features. This is particularly helpful when a fingerprint has been degraded by visual noise such as smudging, dust or other contaminants from a crime scene. Busey said his research indicates that experts in some instances will be able to make sense of fingerprints in a way that novices cannot.

Busey's research interests include human electrophysiology, perception and memory research. He can be reached at 812-855-4261 and busey@indiana.edu. Vanderkolk can be reached at 260-436-7522 and vanderkolkjohn@yahoo.com.